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A127315
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Numbers n such that n^4 divides 19^(n^2)-1.
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0
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OFFSET
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1,2
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COMMENTS
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a(n)^2 are the perfect squares in A128399.
a(10) > 10^13. [From Max Alekseyev]
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LINKS
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MATHEMATICA
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Do[g=PowerMod[19, n^2, n^4]-1; If[IntegerQ[g/n^4], Print[n]], {n, 1, 10000}]
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CROSSREFS
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Cf. A128399 = numbers n such that n^2 divides 19^n-1.
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KEYWORD
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hard,more,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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